This application claims priority of Austrian Application A 749/2000, filed Apr. 28, 2000, the complete disclosure of which is hereby incorporated by reference.
a) Field of the Invention
The invention is directed to a rake cleaning arrangement for a trashrack situated in front of the intake opening of a turbine arrangement, wherein the turbine arrangement is arranged in a weir opening delimited at its sides by two pillars and these pillars delimiting the weir openings are spanned by at least one gangway forming a service platform.
The design of a river power station with a turbine arrangement which can be overflowed, is arranged in an opening between two pillars, and at the same time can fulfill the function of a weir, is known. These pillars are here spanned by a gangway forming a service platform on which a rake cleaning arrangement for cleaning the trashrack of the turbine arrangement is arranged.
b) Description of the Related Art
Rake cleaning arrangements for removing flotsam carried by the inflowing water and accumulated on the trashrack of water power stations are known in different embodiment forms. For example, a skimming arrangement of a rake cleaning arrangement is formed by a chassis frame on which a grab is arranged in a bearing which permits pivoting it on an axle arranged across the working direction of the cleaning apparatus and which can be lowered into the flotsam floating in the water and held back by the rack by means of a tackle line. Then, as soon as there is enough flotsam in front of the raised grab, the grab is operated by means of another tackle line and pivoted towards the chassis frame, by means of which the floating flotsam is gathered. The chassis frame which has been loaded thus is pulled up and emptied and then ready to be used again.
Rake cleaning arrangements can furthermore have a toothed bar the teeth of which extend between the individual bars of the grate when the toothed bar has been pivoted towards the grate. During the downward movement of the chassis frame, the toothed bar is lifted away from the grate and then, during the subsequent upward movement, pivoted towards the grate so that the flotsam is pulled upwards.
A rake cleaner is known from the German patent application DE 1 658 096 for which a cleaning carriage can travel along toothed racks arranged on both sides of the raceway by means of a gear motor and pinions driven by it. A cleaning rake is connected to the cleaning carriage via a cross beam of the cleaning carriage which carries this cleaning rake. By raising and lowering this cross beam forming part of the skimming arrangement, the cleaning rake can travel along the vertical extent of the trashrack.
Further rake cleaning arrangements are known from DE 32 35 458 A and U.S. Pat. No. 5,968,350 A. For the arrangement in DE 32 35 458 A, the skimming arrangement comprises a telescoping extension arm which is coupled to a base in such a way that it can be pivoted by a piston-cylinder-unit and on the free end of which a toothed bar is arranged as a tool. The traveling rake cleaner described in U.S. Pat. No. 5,968,350 A can be moved along rails, wherein a control station is also carried by the traveling carriage to which the extension arm with the tool is coupled.
It can be necessary to construct the pillars limiting the individual weir openings much higher than the water level corresponding to the maximum storage level of the top water. The gangway spanning the pillars here is therefore high above the ordinary level of the top water. This measure must be taken for rivers where the high water can be very high so that this can be let flow away. If a rake cleaning arrangement is here to be operated in a known manner, the skimming arrangement for removing the flotsam has to be lowered far below the service platform until it finally reaches the trashrack. This has disadvantages for the operation, since in particular the service staff is also very far away from the point of use.
It is a primary object of the invention to provide a rake cleaning arrangement which overcomes these disadvantages and can be used advantageously even for service platforms situated high above the usual water level of the top water. According to the invention, this object is met by a rake cleaning arrangement which comprises:
a bridge forming a service platform which can be lowered into the weir opening by means of a crane arranged on top of or on the gangway, and
a skimming arrangement for removing flotsam from the trashrack by means of which a tool can travel along the vertical extent of the trashrack and which is arranged on the bridge, wherein the tool can travel along the vertical extent of the trashrack by means of the skimming arrangement when the bridge is stationary.
It is therefore a basic idea of the invention to realize the rake cleaning arrangement with a height-adjustable service platform, arranged on which there is a skimming arrangement by means of which the tool, for example a toothed bar, can be raised or lowered along the vertical extent of the rack. On this service platform of the bridge forming the rake cleaning arrangement, a control station can be arranged for the operation of the skimming arrangement.
Preferably, the bridge extends essentially across the entire width of the weir opening and is guided by guiding grooves running vertically in the side faces of the pillars facing the bridge. Furthermore, the skimming arrangement is preferably capable of traveling along the lengthwise extent of the bridge. The tool attached to the skimming arrangement preferably realized in the shape of a toothed bar can therefore be narrower than the width of the trashrack, and cleaning the trashrack is done in a number of skimming processes.
Further advantages and details of the invention are subsequently to be described by means of a preferred embodiment example shown in the Figures from which further objects of the invention also emerge.